scientific reasons for explaining the reason why hen has only ywo legs and not foure
2007-02-20 18:07:39 · 9 answers · asked by mak_09_99 1 in Science & Mathematics ➔ Zoology
Pretty much all vertebrates (though I'm not 100% sure about fish) are hardwired to have two pairs of limbs (be they arms, legs, fins, wings etc). Some have lost a pair (eg dolphins), some have lost both pairs (eg snakes), but to my knowledge none have ever gained a pair (except for a few mutants who usually don't live long). So in general, vertebrates only have two pairs of limbs to work with.
Chickens, like most birds, use one pair of their limbs to fly (the wings). Wings are too awkward and fragile to be much use as legs. So since one pair of limbs is occupied with flying, they only have one pair of limbs left to use for walking, aka the legs.
In conclusion: Chickens have four limbs, but because two of them are wings, only two of them are legs.
2007-02-20 19:09:32 · answer #1 · answered by Ombry 3 · 2⤊ 0⤋
not only hens but all birds have 2 legs.its causz they had evolved from dinosaurs who could fly.
originally they had 2 hind limbs and 2 fore limbs but during evolution their fore limbs changed into wings so that they could adopt according to the surroundings.
2007-02-21 05:49:03 · answer #2 · answered by Anonymous · 0⤊ 0⤋
friend,
what i think, this all depends on the evolution of the species.. might be in past they had four legs and with ease to exist with life they develop this kind os morphological structure.
Each and every organisn tend to looose or develop those organs which he think is problem or desired vice versa.
2007-02-21 03:06:26 · answer #3 · answered by Vinay Kala 3 · 0⤊ 0⤋
not only hens, all birds only have two legs because they evolved from dinosaurs that only had two legs.
2007-02-21 02:58:52 · answer #4 · answered by iLoveYOU 2 · 0⤊ 0⤋
They discovered they could not stand on only one leg.
2007-02-24 00:59:55 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Because they have 2 wings.
2007-02-21 02:15:14 · answer #6 · answered by La Niña Mas Linda 3 · 0⤊ 0⤋
so they don't leave a trail like a snail
2007-02-21 02:21:40 · answer #7 · answered by Anonymous · 0⤊ 0⤋
ITS balance so they can walk.
2007-02-21 02:10:31 · answer #8 · answered by Anonymous · 0⤊ 0⤋
FOR IT TO STAND UP :)
2007-02-21 09:53:16 · answer #9 · answered by MORTİCİA 4 · 0⤊ 0⤋